Method Details

read

This method reads bytes from the underlying stream into the specified
byte array buffer. It will attempt to fill the buffer completely, but
may return a short count if there is insufficient data remaining to be
read to fill the buffer.

read

This method reads bytes from the underlying stream into the specified
byte array buffer. It will attempt to read len bytes and
will start storing them at position off into the buffer.
This method can return a short count if there is insufficient data
remaining to be read to complete the desired read length.

readBoolean

This method reads a Java boolean value from an input stream. It does
so by reading a single byte of data. If that byte is zero, then the
value returned is false. If the byte is non-zero, then
the value returned is true.

This method can read a boolean written by an object
implementing the writeBoolean() method in the
DataOutput interface.

readChar

This method reads a Java char value from an input stream.
It operates by reading two bytes from the stream and converting them to
a single 16-bit Java char. The two bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.

As an example, if byte1 and byte2
represent the first and second byte read from the stream
respectively, they will be transformed to a char in
the following manner:

(char)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF)

This method can read a char written by an object
implementing the writeChar() method in the
DataOutput interface.

readDouble

This method reads a Java double value from an input stream. It operates
by first reading a long value from the stream by calling the
readLong() method in this interface, then converts
that long to a double using the
longBitsToDouble method in the class
java.lang.Double

This method can read a double written by an object
implementing the writeDouble() method in the
DataOutput interface.

readFloat

This method reads a Java float value from an input stream. It
operates by first reading an int value from the
stream by calling the readInt() method in this
interface, then converts that int to a
float using the intBitsToFloat method
in the class java.lang.Float

This method can read a float written by an object
implementing the writeFloat() method in the
DataOutput interface.

readFully

This method reads raw bytes into the passed array until the array is
full. Note that this method blocks until the data is available and
throws an exception if there is not enough data left in the stream to
fill the buffer. Note also that zero length buffers are permitted.
In this case, the method will return immediately without reading any
bytes from the stream.

readFully

This method reads raw bytes into the passed array buf
starting
offset bytes into the buffer. The number of bytes read
will be
exactly len. Note that this method blocks until the data is
available and throws an exception if there is not enough data left in
the stream to read len bytes. Note also that zero length
buffers are permitted. In this case, the method will return immediately
without reading any bytes from the stream.

readInt

This method reads a Java int value from an input stream
It operates by reading four bytes from the stream and converting them to
a single Java int. The bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.

As an example, if byte1 through byte4 represent
the first four bytes read from the stream, they will be
transformed to an int in the following manner:

readLine

This method reads the next line of text data from an input
stream. It operates by reading bytes and converting those bytes
to char values by treating the byte read as the low
eight bits of the char and using 0 as the high eight
bits. Because of this, it does not support the full 16-bit
Unicode character set.

The reading of bytes ends when either the end of file or a line
terminator is encountered. The bytes read are then returned as a
String A line terminator is a byte sequence
consisting of either \r, \n or
\r\n. These termination charaters are discarded and
are not returned as part of the string.

This method can read data that was written by an object implementing the
writeLine() method in DataOutput.

readLong

This method reads a Java long value from an input stream
It operates by reading eight bytes from the stream and converting them to
a single Java long. The bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.

As an example, if byte1 through byte8 represent
the first eight bytes read from the stream, they will be
transformed to an long in the following manner:

readShort

This method reads a signed 16-bit value into a Java in from the
stream. It operates by reading two bytes from the stream and
converting them to a single 16-bit Java short. The
two bytes are stored most significant byte first (i.e., "big
endian") regardless of the native host byte ordering.

As an example, if byte1 and byte2
represent the first and second byte read from the stream
respectively, they will be transformed to a short. in
the following manner:

(short)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF))

The value returned is in the range of -32768 to 32767.

This method can read a short written by an object
implementing the writeShort() method in the
DataOutput interface.

readUTF

This method reads a String from an input stream that
is encoded in a modified UTF-8 format. This format has a leading
two byte sequence that contains the remaining number of bytes to
read. This two byte sequence is read using the
readUnsignedShort() method of this interface.

After the number of remaining bytes have been determined, these
bytes are read an transformed into char values.
These char values are encoded in the stream using
either a one, two, or three byte format. The particular format
in use can be determined by examining the first byte read.

If the first byte has a high order bit of 0, then that character
consists on only one byte. This character value consists of
seven bits that are at positions 0 through 6 of the byte. As an
example, if byte1 is the byte read from the stream,
it would be converted to a char like so:

(char)byte1

If the first byte has 110 as its high order bits, then the
character consists of two bytes. The bits that make up the character
value are in positions 0 through 4 of the first byte and bit positions
0 through 5 of the second byte. (The second byte should have
10 as its high order bits). These values are in most significant
byte first (i.e., "big endian") order.

As an example, if byte1 and byte2 are
the first two bytes read respectively, and the high order bits of
them match the patterns which indicate a two byte character
encoding, then they would be converted to a Java
char like so:

(char)(((byte1 & 0x1F) << 6) | (byte2 & 0x3F))

If the first byte has a 1110 as its high order bits, then the
character consists of three bytes. The bits that make up the character
value are in positions 0 through 3 of the first byte and bit positions
0 through 5 of the other two bytes. (The second and third bytes should
have 10 as their high order bits). These values are in most
significant byte first (i.e., "big endian") order.

As an example, if byte1byte2 and
byte3 are the three bytes read, and the high order
bits of them match the patterns which indicate a three byte
character encoding, then they would be converted to a Java
char like so:

Note that all characters are encoded in the method that requires
the fewest number of bytes with the exception of the character
with the value of \u0000 which is encoded as two
bytes. This is a modification of the UTF standard used to
prevent C language style NUL values from appearing
in the byte stream.

This method can read data that was written by an object implementing the
writeUTF() method in DataOutput

readUnsignedShort

This method reads 16 unsigned bits into a Java int value from the stream.
It operates by reading two bytes from the stream and converting them to
a single Java int The two bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.

As an example, if byte1 and byte2
represent the first and second byte read from the stream
respectively, they will be transformed to an int in
the following manner:

(int)(((byte1 & 0xFF) << 8) + (byte2 & 0xFF))

The value returned is in the range of 0 to 65535.

This method can read an unsigned short written by an object
implementing the writeUnsignedShort() method in the
DataOutput interface.

skipBytes

This method attempts to skip and discard the specified number of bytes
in the input stream. It may actually skip fewer bytes than requested.
This method will not skip any bytes if passed a negative number of bytes
to skip.

DataInputStream.java -- FilteredInputStream that implements DataInput
Copyright (C) 1998, 1999, 2000, 2001, 2003, 2005 Free Software Foundation
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module. An independent module is a module which is not derived from
or based on this library. If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so. If you do not wish to do so, delete this
exception statement from your version.